Lois Patrice Griffin (née Pewterschmidt) is one of the main characters of the animated television series Family Guy. She is voiced by writer Alex Borstein and first appeared on television, along with the rest of the family, in the 15-minute short on December 20, 1998. Lois was created and designed by series creator Seth MacFarlane. MacFarlane was asked to pitch a pilot to the Fox Broadcasting Company based on Larry and Steve, a short he made which featured a middle-aged character named Larry and an intellectual dog, Steve. After the pilot was given the green light, the Griffin family appeared on the episode "Death Has a Shadow".

Lois is the mother of the Griffin family. With her husband Peter, she has had three children: Meg, Chris, and Stewie, along with the family dog, Brian. Lois is often portrayed as a stereotypical television mother, despite her admitting to being a recovering methamphetamine addict and a kleptomaniac. Lois has also had several affairs, one of which allegedly resulted in the conception of Meg. She has appeared in other media relating to Family Guy—including a video game, commercials and books—and inspired an entire line of merchandise. Lois's distinctive New York accent originated from a character in a stage show that Alex Borstein performed in, which was largely inspired by a relative who grew up on Long Island, New York.

Family Guy uses a floating timeline in which the characters do not age much, so the show is always assumed to be set in the current year. However, several of the characters, such as Meg Griffin, have aged two to three years since the show's pilot episode, while others, such as Stewie, have remained the same age.[6] In several episodes, events have been linked to specific times, although this timeline has been contradicted in subsequent episodes.

In three months, MacFarlane created the Griffin family and developed a pilot for the show he called Family Guy.[13] Brian's character was largely based on Steve from the Larry and Steve cartoon, with Larry serving as the primary basis of the Peter character.[14] The character's personality was also partially inspired by a friend of his father who rudely fell asleep while watching the 1993 film Philadelphia.[15] The network executives were impressed with the pilot and ordered thirteen episodes, giving MacFarlane a 2 million dollar per-season contract.[13]

"I was asked to audition for the show and at the time I was playing a character in a stage show, so I brought that over and it was very slow, it was based on my cousin from Rhode Island and Seth said that "It would be a four hour show if I talked at that pace so could you make it quicker and raise it".

"Over the years you can notice that it started lower and slower and it's gotten higher and higher and quicker and quicker."

At the time Family Guy was being developed, Borstein was working in the sketch comedy, MADtv.[18] She was asked to audition by a member of the MADtv staff who was helping MacFarlane develop the show. She had not met MacFarlane or seen any artwork and said it was "really sight unseen".[18][19] At the time, she was doing a stage show in Los Angeles, in which she played a redhead mother, whose voice she had based on one of her cousins from Rhode Island.[17][19] She took the voice of the character to the set and use it for Lois. The voice was originally slower, when MacFarlane heard it, he asked her to make it faster and higher. Borstein has noted that the voice of Lois has been changing from the slower original voice to the quicker up tempo voice of the present episodes.[18]

There have been occasions where Borstein does not voice Lois, such as in the episode "Road to the Multiverse", where Lois is not voiced by Borstein in a scene and instead was voiced by Japanese actress Kei Ogawa, who was required for a scene where everything in the world was Japanese (she also did the voice of Meg for the scene).[20]

Lois's personality has evolved throughout the episodes. Lois is commonly the voice of reason to Peter's shenanigans. But in some episodes she can act darker than normal and sometimes shows a taste for sadomasochism. In the episode "The Son Also Draws", Lois showed a gambling addiction when the family went to an Indiancasino and lost the family car. In the episode "Model Misbehavior", Lois becomes a bulimic model. However, in "Sibling Rivalry", just the opposite happens where Lois gains a ton of weight after Peter has a vasectomy and loses his sex drive. As a result, Peter makes fun of her causing her to get even fatter out of spite. He doesn't stop until he discovers just how amazing "fat-sex" is and force feeds her to make her even fatter which in turn will please him. By the end of the episode she is returned to her normal weight by the family doctor after having a heart attack. "Stuck Together, Torn Apart" shows Peter and Lois splitting up because of Peter's jealousy, only to discover that Lois has the same character flaw of jealousy and the two decide to live with their mutually jealous nature.[21] She has also hinted at or been shown using drugs. After the first two seasons, Lois is shown to have more of an egotistical, neglectful, and cold-hearted personality,[22][23][24][25] usually towards Brian or Meg (and later Stewie).

Though she still truly loves Peter, Lois is somewhat promiscuous and has cheated on Peter several times, with older and younger men, sometimes with disastrous consequences. Her extramarital affair with former President Bill Clinton, who was quick to seduce her, would result in temporary separation from Peter. She herself would seduce her daughter Meg's boyfriend, Anthony, and have an affair that would result in the separation of Meg and Anthony. She also passionately kissed Meg's classmate and would-be lesbian girlfriend, Sarah. Lois in fact conceived Meg from an extramarital affair with a man named Stan Thompson. She would cheat on Peter several times when she and Meg became prostitutes to pay for Chris' high class school education, a job in which she ultimately made more money than Meg. Lois has attempted to cheat on Peter with Bob Barker and Justin Bieber, both of whom she unsuccessfully tried to seduce. She has also been shown to have numerous ex-boyfriends, including Gene Simmons of the band KISS and a friend of Peter's named Jerome — both of whom have given her the nickname "Loose Lois". In the episode And I'm Joyce Kinney, it was revealed that Lois had participated in a Pornographic film called "Quest For Fur" in college, which further cemented her promiscuity. This episode has also reveals Lois' mean image in high school as a bullying head cheerleader who bullied and once humiliated Joyce Kinney. In one episode (Lethal Weapons), she shows a violent personality after learning martial arts, which leads to the whole family fighting. Lois's interests are usually pursued in an attempt to separate from Peter, and his antics, or when she feels he's being controlling. She displays an underlying intelligence, and has an interest in the arts.

Many episodes have suggested that Lois is bisexual. In an interview, Borstein stated that Lois became "a little more snarky and sassy and sexual" since the first season to challenge "those sitcom rules that a woman is supposed to be a total wet blanket and not like sex and is no fun".[19] In the first straight-to-DVD feature, Stewie Griffin, The Untold Story, Lois also states, "women are such teases. That's why I went back to men." She reveals in "Partial Terms of Endearment" that she had a lesbian affair with Naomi while they were students at Salve Regina University, and she passionately kisses Meg's lesbian classmate Sarah in "Brian Sings and Swings".

Lois ranked number twelve spot on "IGN's Top 25 Family Guy Characters".[26] In "IGN's top 10 musical moments in Family Guy" ranked number three spot with the song, This House Is Freakin' Sweet from the episode, "Peter, Peter, Caviar Eater", (season 2, 1999).[27] In "IGN's Family Guy: Top 10 Fights", Lois ranked on two places, in number seven and number 6 for Lois's fight with Stewie in "Lois Kills Stewie" and in the Griffin Family Fight from "Barely Legal", respectively.[28]